Differential 3-Ring Electrode PMUTS with High Acoustic Pressure for Glaucoma Optic Neuroprotection

Low-intensity pulsed ultrasound stimulation (LIPUS) is an effective neuromodulatory strategy that prevents ongoing neurodegeneration by non-invasively targeting specific regions and delivering non-thermal acoustic energy to activate neurons precisely. This paper presents a$6 \times 6$high acoustic pressure output piezoelectric micromachined ultrasonic transducer (PMUT) array with a 3-ring electrode structure, which is demonstrated for LIPUS to address the significant medical challenge of neuroprotection in glaucoma. The proposed PMUT array can produce 135 kPa acoustic pressure at 6 mm from the surface and a focused beam with acoustic intensity ($I_{\text {SPTA }}$) up to$364.5 ~\text{mW} / \text{cm}^{2}$. Meanwhile, the JC-1 staining and the Western blot analysis reveal that under specific parameters (60% duty cycle and 1.9 MHz stimulation frequency), the LIPUS significantly mitigates the serum starvation-induced decline in mitochondrial membrane potential$(\Delta \Psi \mathrm{m})(\mathrm{P}